Acute Immune-Mediated Thrombocytopenia due to Oxaliplatin and Irinotecan Therapy

Abstract

We describe a case of a 63-year-old woman with advanced colon cancer and liver metastases who was treated with fluorouracil, leucovorin, and oxaliplatin (FOLFOX) and cetuximab chemotherapy. She tolerated 13 cycles of chemotherapy without any significant hematological side effects, but after the 14th cycle, she developed melena and was admitted for severe thrombocytopenia. After supportive care, the platelet counts rapidly improved to 76,000/μL. Upon initiation of FOLFIRI and cetuximab chemotherapy, she again developed rectal bleeding and severe thrombocytopenia with a platelet count of 6000/μL. Lab testing was positive for oxaliplatin and irinotecan drug-dependent platelet antibodies on flow cytometry assay. Drug-induced thrombocytopenia (DITP) is associated with several classes of drugs with several proposed underlying mechanisms. Prospective studies are needed to further address different mechanisms of drug-induced thrombocytopenia.

Figure 1

Platelet count over time for the two episodes of thrombocytopenia from oxaliplatin and irinotecan infusion with subsequent recovery.

Figure 2

Detection of oxaliplatin-dependent platelet antibodies by flow cytometry. Platelets show high IgG binding when incubated with the patient's serum in the presence of oxaliplatin (0.1 mg/mL) (light gray histogram on the right) compared to platelets incubated with buffer/no drug present (dark histogram in the center). The numbers above each histogram are the median fluorescence intensity (MFI) values.